1. Field of the Invention
The present invention relates generally to methods and compositions for the dry powder formulation of pharmaceuticals, including macromolecules, for pulmonary delivery.
Over the years, certain drugs have been sold in compositions suitable for forming a drug dispersion for oral inhalation (pulmonary delivery) to treat various conditions in humans. Such pulmonary drug delivery compositions are designed to be delivered by inhalation by the patient of a drug dispersion so that the active drug within the dispersion can reach the lung. It has been found that certain drugs delivered to the lung are readily absorbed through the alveolar region directly into blood circulation. Pulmonary delivery is particularly promising for the delivery of macromolecules (proteins, polypeptides and nucleic acids) which are difficult to deliver by other routes of administration. Such pulmonary delivery can be effective both for systemic delivery and for localized delivery to treat diseases of the lungs.
Pulmonary drug delivery can itself be achieved by different approaches, including liquid nebulizers, aerosol-based metered dose inhalers (MDI's), and dry powder dispersion devices. Aerosol-based MDI's are losing favor because they rely on the use of chlorofluorocarbons (CFC's), which are being banned because of their adverse effect on the ozone layer. Dry powder dispersion devices, which do not rely on CFC aerosol technology, are promising for delivering drugs that may be readily formulated as dry powders. Many otherwise labile macromolecules may be stably stored as lyophilized or spray-dried powders by themselves or in combination with suitable powder carriers. The ability to deliver pharmaceutical compositions as dry powders, however, is problematic in certain respects. The dosage of many pharmaceutical compositions is often critical so it is necessary that any dry powder delivery system be able to accurately, precisely, and reliably deliver the intended amount of drug. Moreover, many pharmaceutical compositions are quite expensive. Thus, the ability to efficiently deliver the dry powders with a minimal loss of drug is critical. It is also essential that the powder be readily dispersible prior to inhalation by the patient in order to assure adequate distribution and systemic absorption.
A particularly promising approach for the pulmonary delivery of dry powder drugs utilizes a hand-held device with a hand pump for providing a source of pressurized gas. The pressurized gas is abruptly released through a powder dispersion device, such as a venturi nozzle, and the dispersed powder made available for patient inhalation. While advantageous in many respects, such hand-held devices are problematic in a number of other respects. The particles being delivered are less than 10 μm in size, usually in the range from 1 μm to 5 μm, making powder handling and dispersion more difficult than with larger particles. The problems are exacerbated by the relatively small volumes of pressurized gas, which are available using hand-actuated pumps. In particular, venturi dispersion devices are unsuitable for difficult-to-disperse powders when only small volumes of pressurized gas are available. Another requirement for hand-held and other powder delivery devices is efficiency. It is important that the concentration of drug in the bolus of gas be relatively high to reduce the number of breaths required to achieve a total dosage. The ability to achieve both adequate dispersion and small dispersed volumes is a significant technical challenge that requires in part that each unit dosage of the powdered composition be readily and reliably dispersible.
2. Description of the Relevant Literature
Dry powder dispersion devices for medicaments are described in a number of patent documents. U.S. Pat. No. 3,921,637 describes a manual pump with needles for piercing through a single capsule of powdered medicine. The use of multiple receptacle disks or strips of medication is described in European Patent Application No. EP 0 467 172 (where a reciprocatable punch is used to open a blister pack); International Patent Publication Nos. WO 91/02558; WO 93/09832; U.S. Pat. Nos. 4,627,432; 4,811,731; 5,035,237; 5,048,514; 4,446,862; 5,048,514; and 4,446,862. Other patents which show puncturing of single medication capsules include U.S. Pat. Nos. 4,338,931; 3,991,761; 4,249,526; 4,069,819; 4,995,385; 4,889,114; and 4,884,565; and European Patent Application No. EP 469 814. International Patent Publication No. WO 90/07351 describes a hand-held pump device with a loose powder reservoir.
A dry powder sonic velocity disperser is described in Witham and Gates, Dry Dispersion with Sonic Velocity Nozzles, presented at the workshop on Dissemination Techniques for Smoke and Obscurants, Chemical Systems Laboratory, Aberdeen Proving Ground, Md., Mar. 14-16, 1983.
U.S. Pat. Nos. 4,926,852 and 4,790,305, describe a type of “spacer” for use with a metered dose inhaler. The spacer defines a large cylindrical volume which receives an axially directed burst of drug from a propellant-driven drug supply. U.S. Pat. No. 5,027,806 is an improvement over the '852 and '305 patents, having a conical holding chamber which receives an axial burst of drug. U.S. Pat. No. 4,624,251, describes a nebulizer connected to a mixing chamber to permit a continuous recycling of gas through the nebulizer. U.S. Pat. No. 4,677,975 is described above. European Patent Application No. 0 347 779 describes an expandable spacer for a metered dose inhaler having a one-way valve on the mouthpiece. International Patent Publication No. WO 90/07351 describes a dry powder oral inhaler having a pressurized gas source (a piston pump) which draws a measured amount of powder into a venturi arrangement.
The respiratory delivery of aerosolized aqueous insulin solutions is described in a number of references, beginning with Gänsslen (1925) Klin. Wochenschr. 4:71 and including Laube et al. (1993) JAMA 269:2106-21-9; Elliott et al. (1987) Aust. Paediatr. J. 23:293-297; Wigley et al. (1971) Diabetes 20:552-556. Corthorpe et al. (1992) Pharm Res 9:764-768; Govinda (1959) Indian J. Physiol. Pharmacol. 3:161-167; Hastings et al. (1992) J. Appl. Physiol. 73:1310-1316; Liu et al. (1993) JAMA 269:2106-2109; Nagano et al. (1985) Jikeikai Med. J. 32:503-506; Sakr (1992) Int. J. Phar. 86:1-7; and Yoshida et al. (1987) Clin. Res. 35:160-166. Pulmonary delivery of dry powder medicaments, such as insulin, in a large particle carrier vehicle is described in U.S. Pat. No. 5,254,330. A metered dose inhaler (MDI) for delivering crystalline insulin suspended in a propellant is described in Lee and Sciara (1976) J. Pharm. Sci. 65:567-572. A MDI for delivering insulin into a spacer for regulating inhalation flow rate is described in U.S. Pat. No. 5,320,094. The intrabronchial administration of recombinant insulin is briefly described in Schluter et al. (Abstract) (1984) Diabetes 33:75A and Köhler et al. (1987) Atemw. Lungenkrkh. 13:230-232. Intranasal and respiratory delivery of a variety of polypeptides, including insulin, in the presence of an enhancer, are described in U.S. Pat. No. 5,011,678 and Nagai et al. (1984) J. Contr. Rel. 1:15-22. Intranasal delivery of insulin in the presence of enhancers and/or contained in controlled release formulations are described in U.S. Pat. Nos. 5,204,108; 4,294,829; and 4,153,689; International Patent Publication Nos. WO 93/02712, WO 91/02545, WO 90/09780, and WO 88/04556; Great Britain Patent No. 1,527,605; Ryden and Edman (1992) Int. J. Pharm. 83:1-10; and Bjork and Edman (1988) Int. J. Pharm. 47:233-238. The preparation and stability of amorphous insulin were described by Rigsbee and Pikal at the American Association of Pharmaceutical Sciences (AAPS), Nov. 14-18, 1993, Lake Buena Vista, Fla. Methods for spray drying polypeptide, polynucleotide and other labile drugs in a carrier which forms an amorphous structure which stabilizes the drug are described in European Patent Application No. 520 748. (AAPS), Nov. 14-18, 1993, Lake Buena Vista, Fla.
Stribling et al. (1992) J. Biopharm. Sci. 3:255-263, describes the aerosol delivery of plasmids carrying a chloramphenicol acetyltransferase (CAT) reporter gene to mice. The plasmids were incorporated in DOTMA or cholesterol liposomes, and aqueous suspensions of the liposomes were nebulized into a small animal aerosol delivery chamber. Mice breathing the aerosol were found to at least transiently express CAT activity in their lung cells. Rosenfeld et al. (1991) Science: 252:431-434, describes the in vivo delivery of an alpha-1 antitrypsin gene to rats, with secretion of the gene product being observable for at least one week. The gene was diluted in saline and instilled directly into the rat trachea. Friedman (1989) Science 244:1275-1281 is a review article describing human gene therapy strategies.
U.S. Pat. Nos. 4,833,125 and 4,698,328, describe the administration of active parathyroid hormone fragments in combination with vitamin D or a dietary calcium supplement. Suggested administration routes include parenteral by injection, rapid infusion, nasopharyngeal absorption, dermal absorption, or oral. See also, Neer et al. (1987) Osteoporosis 53:829-835. U.S. Pat. No. 5,011,678, describes the use of amphophilic steroids as a penetration enhancer for nasal or bronchopulmonary delivery of proteins and polypeptides, listing parathyroid hormone as one of a “veritable host” of proteins which could be delivered with the enhancer. Parathyroid hormone (full length) is secreted naturally from the parathyroid gland as a series of spikes in a pulsatile fashion which is analogous to pituitary hormones (Harms et al. (1987) Int. Symp. on Osteoporosis, Aalborg, Abstract 232). The full length hormone is rapidly broken down in the circulation into several fragments which are the dominant serum forms. It is hypothesized that an intermittent or pulsatile secretion pattern for parathyroid hormone is necessary to maintain its bone restoring properties (Hesch et al. (1988) Calcif. Tissue Int. 42:341-344 and Habener et al. (1971). Proc. Natl. Acad. Sci USA 68:2986-2991). Patton and Platz (1992) Adv. Drug Deliver. Rev. 8:179-196, describe methods for delivering proteins and polypeptides by inhalation through the deep lung.
The aerosolization of protein therapeutic agents, including alpha-1 antitrypsin, is disclosed in European Patent Application No. EP 0 289 336. The use of alpha-1 antityrpsin for treating pulmonary inflammation is disclosed in U.S. Pat. No. 5,093,316.
Therapeutic aerosol formulations, including calcitonin, are disclosed in International Patent Publication No. WO 90/09781.
Methods and compositions for inhibiting neutrophil elastase and cathespin G employing aerosolized 2-0-desulfated heparin are disclosed in International Patent Publication No. WO 94/02107.
Interleukin-1 receptor compositions are disclosed in U.S. Pat. Nos. 4,968,607, 5,081,228 and 5,180,812.
Aerosol formulations of interferons have been produced for pulmonary delivery as described in International Patent Publication No. WO 91/16038. International Patent Publication No. WO 91/16038 teaches adding a surfactant or the like to improve the dispersibility of a human interferon from a CFC delivery system. Methods and compositions for the preparation of solid polypeptide microparticles as a pharmaceutical aerosol formulation are disclosed in International Patent Publication No. WO 91/16038. The purification of proteins of molecular weight in excess of 12,000, including human IFN is disclosed in U.S. Pat. No. 4,503,035. Low pH pharmaceutical compositions of recombinant IFN-beta are disclosed in International Patent Publication No. WO 89/05158.
3. Objects of the Invention
An object of the present invention is to provide a pharmaceutical composition suitable for long-term pulmonary administration to a patient in need thereof.
Another object of this invention is to provide a pharmaceutical-containing dispersible dry powdered composition that is administered by inhalation in a manner that is free of a liquid propellant such as a CFC, HFC or carbon dioxide.
Another object of this invention is to provide a pharmaceutical-containing dispersible dry powdered composition that can be easily manufactured by a method that maintains a high percentage of pharmaceutical activity.
Another object of this invention is to provide a manufacturable method for the production of a pharmaceutical composition of sufficient purity.
Still another object of this invention is to provide a pharmaceutical-containing dispersible dry powdered composition that exhibits a high level of stability.
Other objects may be apparent to one of ordinary skill upon reviewing the following specification and claims.